1. Field of the Invention
This invention relates to a dust collecting cell used for the dust collector in an electronic air cleaner, or like device.
2. Description of the Prior Art
There is known a dust collecting cell constructed as shown in FIG. 1. The cell comprises a plurality of positive electrode plates 1 and a plurality of negative electrode plates 2 lying alternately with the positive electrode plates 1 in a parallel and appropriately spaced apart relation thereto. Each electrode plate 1 or 2 is, for example, a thin sheet of aluminum. The cell also includes a high voltage power source 3 adapted to supply a positive charge of high voltage to the positive electrode plates 1 and a negative charge of high voltage to the negative electrode plates 2. If high voltage is applied to the positive and negative electrode plates 1 and 2, fine particles of dust passing between the adjoining electrode plates are electrostatically attracted thereto and are thereby collected.
In the cell as shown in FIG. 1, however, the positive and negative electrode plates 1 and 2 are both of the same potential and are connected in parallel to each other. Therefore, an electric charge defined as Q=C.multidot.V is accumulated between the electrode plates, as is the case with a capacitor using air as a dielectric. If a coarse particle of waste enters the cell between any pair of adjoining electrode plates 1 and 2, it causes a dielectric breakdown resulting not only in the discharge of the electricity which has been accumulated therebetween, but also in the discharge of the electricity accumulated between any other pair of electrode plates which occurs through that part of the cell in which the dielectric breakdown has occurred. The discharge makes a very large noise.
Another known cell construction is shown in FIG. 2. It includes an insulating resin 10 covering each electrode of one polarity (in FIG. 2, each positive electrode plate 1) to realize a higher withstand voltage to thereby prevent any dielectric breakdown. In this form of construction, however, the reliability of the insulating resin 10 is critical. Its reliability is easily lowered or lost if it has any pinhole, or is flawed during the fabrication of the cell or during its use, as when it is cleansed, or if it is deteriorated by a strongly alkaline solution used for cleansing the cell, by the ozone which is generated upon application of high voltage, or by the ultraviolet radiation which is applied to the cell to kill the bacteria which have propagated in the contaminated portions of the cell.